The aim of this program is to analyze the basic hormonal mechanisms of insects and second, to examine the possibilities of using hormonally active materials as safe insecticides for the control of pests and vectors of disease. We have developed new approaches to the problems of hormonal mechanisms in insects, by using genetic mutants and techniques in the fruit fly Drosophila. One approach is the selection and analysis of mutants which are defective in their endocrine systems or in the responses of the target tissues. Such mutants will be analyzed by means of endocrinological and biochemical techniques as well as by genetic techniques such as the analysis of the behavior of mosaics produced in gynandromorphs and by X-ray induced somatic recombination. This combined use of genetics and insect physiology should enable us to dissect complex endocrine machanisms into individual gene-controlled steps, and permit a much more detailed analysis than is possible in the more conventional organisms used by insect endocrinologists. We have undertaken the isolation and identification of the juvenile hormones of Diptera and of Thysanura employing new isolation procedures. We are also interested in the possibility of using insect hormone analogues, such as ecdysones and juvenile hormone analogues, as safe insecticides. In this connection we are examining the effects of insect hormones on arthropods other than insects, especially the isopod crustacean, Armadillidium. In addition to gaining some new insights into comparative endocrinology, we hope to learn what other organisms besides insects may be affected by analogues of insect hormones.